Nonzero orbital moment in high coercivity ε-Fe2O3 and low-temperature collapse of the magnetocrystalline anisotropy

被引：109

作者：

Tseng, Yuan-Chieh ^{[1
,2
]}

Souza-Neto, Narcizo M. ^{[1
]}

Haskel, Daniel ^{[1
]}

Gich, Marti ^{[3
]}

Frontera, Carlos ^{[4
]}

Roig, Anna ^{[4
]}

van Veenendaal, Michel ^{[1
,5
]}

Nogues, Josep ^{[6
,7
]}

机构：

[1] Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USA

[2] Northwestern Univ, Dept Mat Sci & Engn, Evanston, IL 60201 USA

[3] St Gobain Res, F-93303 Aubervilliers, France

[4] ICMAB CSIC, Bellaterra 08193, Catalunya, Spain

[5] No Illinois Univ, Dept Phys, De Kalb, IL 60115 USA

[6] ICREA, Bellaterra 08193, Catalunya, Spain

[7] Ctr Invest Nanociencia & Nanotecnol ICN CSIC, Bellaterra 08193, Catalunya, Spain

来源：

PHYSICAL REVIEW B | 2009年 / 79卷 / 09期

关键词：

bond lengths; coercive force; iron compounds; magnetic anisotropy; magnetic circular dichroism; magnetic moments; magnetisation; magnetoelectric effects; nanoparticles; permanent magnets; spin-orbit interactions; sum rules; RAY CIRCULAR-DICHROISM; MAGNETIC-PROPERTIES; NANOPARTICLES; TRANSITION; COBALT; PHASE; IRON; NANOCOMPOSITE; FIELDS;

D O I：

10.1103/PhysRevB.79.094404

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

The magnetic properties of epsilon-Fe2O3 nanoparticles are investigated by x-ray magnetic circular dichroism. Sum rules relating the orbital and spin moment in the Fe 3d band to the Fe L-2,L-3 absorption cross sections show that the Fe orbital moment (m(orb)) is considerably high, explaining the origin of the large coercivity of this material at room temperature. Moreover, at T similar to 110 K, the collapse of the coercivity (H-c) and the magnetocrystalline anisotropy coincides with a strong reduction of the spin-orbit coupling evidenced by a drastic drop of m(orb). The decrease in m(orb) originates from changes in the electron transfer between Fe and O ions accompanied by significant modifications of some of the Fe-O bond distances. Similarly, the recovery of m(orb) at lower temperatures mimics the behavior of the Fe-O bond lengths.

引用

页数：6

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